DO “WARM UP” EXERCISES IMPACT UTILITY? EVALUATING ANCHORING BIAS IN PEDIATRIC UTILITY ELICITATION

Purpose: “Warm-up” scenarios and questions can familiarize respondents with the format of disease state descriptions and concept of health state rating prior to querying a condition of interest.  It is unclear whether such warm-up scenarios introduce anchoring bias that subsequently impacts utility estimates for the condition being investigated.  We sought to compare estimates of the utility of a common pediatric condition, vesicoureteral reflux (VUR), following respondent exposure to practice scenarios involving conditions with differential impact on health-related quality of life.

Method: A time-trade-off (TTO) elicitation instrument was published through an online work interface, Amazon’s Mechanical Turk (mTurk).  Respondents were randomly selected to answer paralysis or common-cold warm-up exercises, or to skip the warm-up exercise entirely.  All respondents then answered questions from a child-parent dyad perspective on the utility of a single VUR health state in an affected 6-year-old child. VUR utility estimates were then calculated and compared using bivariate and multivariate analyses.

Result: In total, we obtained 753 responses.  Mean respondent age was 35 (±11) years; 369 (49%) were female; 536 (71%) were white; 324 (43%) were married; and 368 (49%) had children.  Most respondents stated they had no previous knowledge of VUR (608, 81%), though some had previous experience with VUR either in a child (26, 3%) or a friend/relative (35, 5%).  We randomly assigned 258 to the paraplegia scenario, 255 to the common cold scenario, and 240 to bypass the warm-up scenario altogether.  VUR utilities were 0.8678, 0.8770, and 0.8713 in the paralysis, common cold, and no-warm-up groups respectively (p=0.17, Kruskal-Wallis).  After adjusting for previous experience with VUR (present in either a child or a friend/relation), ethnicity, and race, VUR utility was not significantly affected (p=0.87) by the presence or type of TTO warm-up scenario. 

Conclusion: The use of a warm-up state does not appear to significantly alter TTO utility estimates for pediatric utilities.